To utilize solar energy for heating and ultimately for electricity generation it is generally necessary to concentrate the solar radiation to obtain higher temperatures in the energy storage and transport medium.
There are various methods used to concentrate the solar radiation. One method utilizes a circular mirror of parabolic section with the center line of the dish pointing at the sun. The parabolic mirror must be suitably mounted to permit constant movement to follow the arc of the sun through the sky.
Additionally, the alignment of the arc of the sun through the sky will change from day to day as the declination of the sun changes from summer solstice to the winter solstice. Complex mechanisms are required to fulfill these requirements.
In the above method, the solar energy is concentrated into a small single focus point where a suitable heat absorber is mounted and it is difficult to transport this energy to a utilization point.
In another system, long parallel mirrored troughs having a parabolic cross section are aligned with the sun. In this system, the concentration occurs at a focus line parallel with the alignments of the collecting troughs.
The collecting troughs may be aligned in a North-South direction and the troughs are so mounted as to permit them to follow the movement of the sun through the course of the day. Complex mechanisms are also required to fulfill this requirement.
The solar energy is then generally collected in a pipe containing a suitable heat absorbing liquid, the pipe being mounted at the focus line of the parabolic reflecting troughs.
In the trough collecting system, the troughs can also be mounted in an East-West alignment and it is then necessary to align the troughs to the arc line of the sun once each day to allow for change in declination. Complex mechanisms are also required to control this alignment.
In mounting parabolic reflecting troughs in either the North-South or the East-West configuration, the troughs are adjusted to maintain their focus on the sun by pivotally mounting on an axis parallel to the focus line of the collecting mirrors and generally requiring a multiplicity of rotating bearings and associated mounting structures.
It is, of course, important to properly support the reflecting troughs so that they do not bend or break, since such deformations will reduce their ability to reflect the solar energy to the focus line. However, due to the large size of such solar collectors (the amount of energy collected being essentially directly related to the area of the reflectors), such supports can be cumbersome and thereby not only expensive to build but also more difficult to move to maintain proper alignment of the reflectors such as previously discussed.
Also, it is generally necessary to arrange the reflecting surfaces of solar energy collecting apparatus so that they are not subject to the possibility of damage caused by such things as hail. This is often achieved by the use of high quality and consequently expensive toughened glass in the construction of the reflecting mirrors. Further protection against hail could be achieved by turning the mirrored surfaces away from the direction of on coming hail, or the use of large screens which may be moved over the top of the whole mirror system. However, either structure is necessarily complex and expensive, and can require considerable structural support to withstand strong winds.
It is an object of the present invention to overcome or substantially ameliorate the above-described disadvantages.